Elastic Flexure Example - Singly Symmetric I-shape

In this example, which is similar to an earlier example, singly symmetric built-up I-shaped steel beam composed of a 6”x1” top flange, a 10”x1” bottom flange, and a 20”x1/2” web, is analyzed. Unlike a doubly symmetric section, this beam's centroid is offset from the geometric center, and was found by calculations to be located 12.62” below the top and 9.385” above the bottom of the section. The moment of inertia was determined to be 2,031 in^4, which results in different elastic section moduli for the top and bottom fibers. Under an applied bending moment of 600 k-ft, the section experiences a compressive stress of 44.72 ksi at the top fiber and a tensile stress of 33.27 ksi at the bottom fiber. Finally, the yield moment - the moment causing first yielding in the extreme fibers - was found to be 670.8 k-ft, occurring at the top fiber because it is further from the neutral axis.